code: def teardown_method(self):
      # Delete so that all the subprocesses are joined
      del self.vec_env
  
file_path: pfrl/tests/envs_tests/test_vector_envs.py
imports: import gym
  import numpy
  import pytest
  import pfrl
label_desc: Use image node_id 2 for calling the TestSerialVectorEnv obj's underlying member method code with example usage: obj.teardown_method() without return types